EIM Guide: Network Master User Guide for Allen Bradley Series PLC-5 Programmable Controller Manuals & Guides

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User’s Guide

AB1771-C

Network Master

(Version 5.21)

For

Allen-Bradley Series PLC-5 Programmable Controllers

(Date: 2004-11-18)

Controlinc 1771-C (Version 5.21) Network Master Users Guide (2004-11-18)

User’s Guide

Controlinc Network Master … AB1771-C (Version 5.21)

For

Allen-Bradley Series PLC-5 Programmable Controllers

Table of Contents

0. Quick Start Information...............................................................................1

1. Introduction...................................................................................................2

1.1. Overview of 1771-C System ................................................................................... 2

1.2. Overview of Changes in Version 5.21 ................................................................... 4

1.3. Reference Manuals ................................................................................................. 6

1.4. EIM Equipment Compatibility .............................................................................7

1.5. Firmware ................................................................................................................. 7

2. 1771-C Hardware..........................................................................................8

2.1. Hardware Setup ...................................................................................................... 8

2.2. LED Utilization ....................................................................................................... 9

2.2.1. Green (PTX & PTR) and Yellow (LED1 & LED2) LED Usage ...............................9

2.2.2. Red “BTL” LED Usage.........................................................................................11

3. Network Setup and Connecting to the NIU ..............................................12

3.1. Field Connections at the Actuator....................................................................... 14

3.1.1. Step 1. Plan the Network Topology ................................................................... 14

3.1.2. Step 2. Select Network Cable............................................................................14

3.1.3. Step 3. Route Cable away from Electrical Interference ..................................... 15

3.1.4. Step 4. Observe Polarity and Network Grounding ............................................. 15

3.1.5. Step 5. Wire Preparation and Connections........................................................ 15

3.1.6. Step 6. Test Network ......................................................................................... 15

3.2. Field Network Cable Connection to the NIU ..................................................... 16

3.3. Cable Connection Between the NIU and the Network Master ........................ 16

4. 1771-C General Theory of Operation .......................................................17

4.1. Operational Overview ..........................................................................................17

4.1.1. Diagram Describing Relationship Between Process Time Slices ........................ 17

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Controlinc 1771-C (Version 5.21) Network Master Users Guide (2004-11-18)

4.1.2. Diagram Describing Network Scanning & Actuator Writing Logic........................18

4.1.3. Diagram Demonstrating Adding Additional Valves in Valve Scan Time-Slice...... 19

4.1.4. Diagram Describing Relationship Between Scan Period & Diagnostic Scan....... 20

4.1.5. 1771-C System Operations at Power Up.............................................................21

4.2. Network Interface (Scan) Time-Slice (1771-C ↔ Network Communication) 22

4.2.1. Operation: Network Scanning to Gather Valve Actuator Data ............................ 22

4.2.2. Operation: The Network Communication Diagnostic Scan................................. 23

4.3. PLC Interface Time-Slice (1771-C ↔ PLC Communication)..........................25

4.3.1. Operation: PLC (Write Data Tables To) or (Read Tables From) the 1771-C...... 27

4.3.2. Operation: PLC Commands to Write Data to the Actuators................................ 30

4.3.3. RLL Example … Manually Send New Table … Auto Read Response ................ 32

5. System Tables..............................................................................................33

5.1. Table Arrangement............................................................................................... 35

5.2. Standard Header Format (All Tables) … Words [0  3] ................................37

5.2.1. Word [0]: Table ID............................................................................................. 37

5.2.2. Word [1]: Read / Write Command Indicator ......................................................37

5.2.3. Word [2]: Reserved / Firmware ID..................................................................... 37

5.2.4. Word [3]: Emergency Shut Down (ESD) Command Word & Indication ............ 38

5.3. Table [0] … System Information Table.............................................................. 39

5.3.1. Table [0] Overview............................................................................................... 39

5.3.2. Table [0] Configuration Words … Words [4 17]................................................ 42

5.3.3. Table [0] Run-Time Information Words … Words [47 63] ................................47

5.3.4. Table [0] … RSLOGIX-5 Examples ..................................................................... 48

5.3.4.1. Example RSLOGIX-5 Screen: ..............................................................................48

5.3.4.2. Table [0] … The Configuration Values (RSLOGIX-5). ......................................... 49

5.3.4.3. Table [0] … The Configuration Values – Writing Table [0] (RSLOGIX-5) ............50

5.3.4.4. Table [0] … The Run-Time Feedback Values From 1771-C (RSLOGIX-5).........51

5.4. Tables [1  20] … Actuator Information Tables..............................................52

5.4.1. Table [1]: Communication Error Status............................................................... 52

5.4.2. Table [2]: Actuator Operational Status................................................................ 54

5.4.3. Table [3]: Discrete Control Mode (Open/Close/Stop) .........................................56

5.4.4. Table [4]: Valve Position Indication … 0 – 100.0% ............................................. 58

5.4.5. Table [5]: Valve Position Setpoint … 0 – 4095 ...................................................59

5.4.6. Tables [6 & 7]: User Analog Inputs #1 & 2.......................................................... 61

5.4.7. Table [8]: Analog Output #1................................................................................62

5.4.8. Tables [9 & 10]: Digital Input Accumulators (Totalizers) #1 & 2..........................64

5.4.9. Table [11]: Valve Position Indication … 0 – 4095 ............................................... 66

5.4.10. Table [12]: Discrete Input Statuses................................................................... 67

5.4.11. Table [13]: Solid State Relay (SSR) Configuration Table .................................69

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Controlinc 1771-C (Version 5.21) Network Master Users Guide (2004-11-18)

5.4.12. Table [14]: Additional Register Being Polled From Entire Network...................71

5.4.13. Table [15]: Additional Block of Registers Being Polled From 1 Actuator........... 73

5.4.14. Tables [16 & 17]: Monitor & Control Discrete Digital Outputs ........................... 76

5.4.15. Table [18]: Actuator System Type ID................................................................ 80

5.4.16. Table [19]: Actuator Firmware Version ID.........................................................82

5.4.17. Table [20]: Modbus Exception Message Response.......................................... 83

5.4.18. Tables [21-24]: TEC2000 Status Inputs............................................................ 85

6. Application Notes ........................................................................................87

6.1. App Note: Performance Tuning ......................................................................... 87

6.1.1. General Practices to Ensure Better Performance................................................87

6.1.2. Reading Run-Time Information from Table [0]..................................................... 87

6.1.3. Loading Table [0] with Configuration Information ................................................88

6.1.4. Behavior if a Delay in Loading Table [0] Configuration Information ..................... 89

6.1.5. Using the “Scan Period” Value ............................................................................90

6.2. App Note: 1771-C Operation – Additional Detailed Information .................. 91

6.2.1. Determining & Exiting “Network Down” Condition ...............................................91

6.2.2. Detailed Description of 1771-C Operation ........................................................... 92

6.2.3. Time Allocated Process Control (Allocated Time Slices)..................................... 93

6.2.4. Preferred Communication Port Operation............................................................ 95

6.2.5. Communication Failure Indications (Low-Level & High-Level)............................. 96

6.2.6. Bringing Units On-Line After a Power Cycle ........................................................ 99

6.2.7. Toggling the Preferred Port to Assist Diagnostics ............................................. 100

6.3. App Note: For Diagnostics - Know the Physical Network Wiring ...............101

6.4. App Note: Memory Maps ................................................................................. 102

6.4.1. Specific Holding Registers Referenced by the Network Master......................... 102

6.4.2. Specific Coils & Inputs Referenced by the Network Master............................... 103

6.4.3. 320A Memory Map … Table for Coils & Inputs (Version 2.0) ............................104

6.4.4. 320A Memory Map … Addressable Holding Registers (Version 2.0) ................ 105

6.4.5. 320B Memory Map … Table for Coils & Inputs.................................................. 107

6.4.6. 320B Memory Map … Addressable Holding Registers...................................... 108

6.4.7. TEC2000 Memory Map … Table for Coils & Inputs........................................... 110

6.4.8. TEC2000 Memory Map … Table for Holding Registers..................................... 111

6.5. App Note: Modbus Message Formats..............................................................116

6.5.1. Modbus RTU Functions (Command Codes) Implemented ................................ 116

6.5.2. Modbus Function (Command) Code Descriptions ............................................. 117

6.5.2.1. Modbus Function Code 01 … Read Coil Status .................................................117

6.5.2.2. Modbus Function Code 03 … Read Holding Register........................................118

6.5.2.3. Modbus Function Code 05 … Set (Force) Single Coil........................................119

6.5.2.4. Modbus Function Code 06 … Set Single Register .............................................120

6.5.2.5. Modbus Function Code 15 (0x0F) … Set (Force) Multiple Coils ........................121

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Controlinc 1771-C (Version 5.21) Network Master Users Guide (2004-11-18)

6.5.3. Modbus Exception Messages Supported .......................................................... 122

6.6. App Note: Install the 1771-C Network Master Firmware............................. 123

6.6.1. Configure the Module for a Firmware Upload .................................................... 124

6.6.2. Upload the 1771-C Firmware............................................................................. 125

6.6.3. Reset the 1771-C Module for Normal Operations.............................................. 126

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Controlinc 1771-C (Version 5.21) Network Master Users Guide (2004-11-18)

0. Quick Start Information

1. As a minimum, you should have access to the following reference documents:

• This manual (1771-C User’s Guide)

• Allen-Bradley 1771-DB, Series B Basic Module User's Manual

Catalog No. 1771-DB, Series B, Publication No. 1771-6.5.113

• EIM Controlinc 320A Quick Startup Guide, Rev. F or later

• EIM Controlinc 320B Quick Startup Guide, Rev. A or later

2. Refer to Section 2 of this manual on how the jumpers should be set on the DB module.

3. The 1771-C module comes from EIM pre-programmed with the network master program in it. However, if for some reason the module needs to be flashed again (ex: a field upgrade) then refer to Section 5 on installing the firmware in the module.

Note: Remember, you will need to connect a serial cable between the 1771-C and the computer. The

correct cable is a Null Modem Cable connector on the module) and the serial communications port on the computer used for the upload.

4. Ensure the PLC rack power is turned off. Install the module in the correct slot in the PLC rack. Connect all cables and power the system up.

5. The PLC-RLL will start interfacing with the 1771-C after the 1771-C performs initial scans of the network on power up.

NOTES: To ensure optimal performance, some things the PLC should do …

1. Ensure table [0] is set correctly and repeated in a timely manner. Allow for frequent table [0] read backs.

2. Restrict the rate of data writes to the actuators … only write as fast as required to adequately control the valve. (cuts down on the interruptions to scanning the network … gathering data)

3. Expedite responses to BTW/BTR requests made by the 1771-C. Delaying them can slow 1771-C operations.

4. Only activate writing to or reading from tables if actually in use (or when needed). (ex: do not write to the analog output table if analog outputs are not used) (ex: do not read totalizer data if its not being used) (ex: only poll for “static” [non-changing] data one time and stop)

(prevents unnecessary delays to gathering the more important data from the network)

Remember:

The 1771-C uses explicit read/write commanding of the tables such that if word [1] in any table is

zero (0) then it is a table read request by the PLC. Otherwise, the command is a table write command.

connected between the PRT1 port (bottom DB25

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Controlinc 1771-C (Version 5.21) Network Master Users Guide (2004-11-18)

1. Introduction

1.1. Overview of 1771-C System

This document is intended for end users as a Guide in applying an EIM AB 1771-C Network Master.

The software that enables network operation is called a communication driver. It is used in conjunction with an Allen-Bradley 1771-DB Series B module thereby creating the 1771-C network master module. The 1771-C allows an AB PLC-5 controller to acquire data from and send information to an EIM Controlinc Actuator Network.

Other than changes to tables [11 & 12], version 5.21 is fully backwards compatible with version 5.03.

GENERAL SYSTEM PURPOSE:

The EIM 1771-C network master serves as a data concentrator for applications that use an AB PLC-5 Programmable Logic Controller (PLC).

In general, the network master off-loads network communication and management tasks from the actual controlling equipment. The main function of the 1771-C is to provide the interface between a PLC and its network of valve actuators. Acting as a Host, the PLC controls the network by sending data to the 1771-C for routing to a particular actuator. The 1771-C network master polls the individual actuators for information and makes it available to the PLC when requested.

A typical ring topology network and network master are illustrated in Figure 1. The 1771-C module serves as a master within this Modbus (Modbus RTU) master/slave network. The module will manage network operation by keeping an orderly cycle of data transfers between itself and each slave (valve actuator).

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Controlinc 1771-C (Version 5.21) Network Master Users Guide (2004-11-18)

The 1771-C master will handle network communication, error detection, alarming, and network recovery. Other features include:

• Reporting of inaccessible actuators

• Reporting of network faults

• Emergency shutdown broadcasting

• Minimal Interfacing with the Relay Ladder Logic (RLL) program in the PLC CPU module

Each 1771-C module can support a single network of up to 60 valve actuators. Multiple modules can be installed in a PLC-5 system rack to provide support for multiple networks (up to 60 actuators each).

Note 1: It is important to note that the 1771-C Network Master may be used in any slot in the 1771

rack, not just slot 0 next to the PLC-5 CPU. It may also be located in remote 1771 racks.

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Controlinc 1771-C (Version 5.21) Network Master Users Guide (2004-11-18)

1.2. Overview of Changes in Version 5.21

Any later releases of this document for this version of the product (5.21) are to only correct entries in this document … primarily grammatical or “typos” that are discovered in the future. Major ideas will be documented with a separate “line entry”.

Major document changes:

1. This document: 2004-11-18 Previous document: 2004-08-17 Major Change: Memory Maps adjusted.

2. New document: 2004-08-17 Previous document: 2004-08-06 Major Changes: Memory Maps adjusted and this section added.

5.20  5.21

The following list identifies the most significant functional changes between version 5.20 and 5.21.

1. Table [17] was changed from read-only to read-write to allow an end user to clear it.

5.03  5.20 The following list identifies most significant functional changes between version 5.03 and 5.20.

1. The previous firmware release: version 5.03.

2. The number of tables increased …

• Version 5.03 … tables [0 - 13]

• Version 5.20 … tables [0 - 24]

3. Table [11] has a different function …

• Version 5.03 … indicate the status of digital input #1.

• Version 5.20 … indicate the valve’s current position in 0-4095 increments … register

[14].

4. Table [12] has a different function …

• Version 5.03 … indicate the status of digital input #2.

• Version 5.20 … indicate the status of all the actuator’s discrete inputs … register [05].

5. Additional system configuration words in table [0] …

• Version 5.03 … words [4 - 7]

• Version 5.20 … words [4 – 17]

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Controlinc 1771-C (Version 5.21) Network Master Users Guide (2004-11-18)

6. Run-Time data words in table [0] …

• Version 5.03 … words [49 – 63]

• Version 5.20 … words [47 – 63]

7. System Diagnostic Scan …

• Tests both ports … Identifies node system type … Table [18]

• Only one port … Identifies firmware Version ID … Table [19]

Gathers standard scan data.

8. Faster “full network response on power up” if power cycled on entire network.

9. Implemented Scan Period Counter (Accumulator) in table [0] … words [47 & 48] and the ability for the operator to reset the counter using table [0] … words [15 & 16].

10. Separated communication errors such that if the error is due to the actuator (slave) responding with a Modbus exception code (the low level communication was ok … however, the actuator rejected it with an exception), the 1771-C now …

- does NOT report this as a communication error … table [1].

- records the exception code and error code sent by the actuator … table [20].

- clears the exception code on the next diagnostic scan.

11. Compatibility with multiple EIM equipment types (320A, 320B, TEC2000).

• Types are identified in table [18]

• 320A & 320B Firmware version ID is identified in table [19]

• 1771-C will check & test for SSR bit only if a 320A node.

12. User Configurable “Additional Message Response Delay Time

” …

• Configure … table [0] … word [8]

13. User Configurable “Poll Specific Register From All Nodes on Network

” …

• Configure … table [0] … words [9 & 10]

• The response is in table [14].

14. User Configurable “Poll Block of Registers From a Specific Node on the Network

” …

• Configure … table [0] … words [11 - 14]

• The response is in table [15].

15. User Configurable “Control Discrete Digital Outputs

…

• Configure … table [16]

• Monitoring the status of the outputs is in table [17].

16. User Configurable “Poll TEC2000 Inputs … registers [1000-1003]

” …

• Configure … table [0] … word [17]

• Response … tables [21-24]

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Controlinc 1771-C (Version 5.21) Network Master Users Guide (2004-11-18)

1.3. Reference Manuals

• Allen-Bradley 1771-DB, Series B Basic Module User's Manual

Catalog No. 1771-DB, Series B, Publication No. 1771-6.5.113

This manual is required for proper uploading of this driver into the hardware. It includes specific information on Call Routines and handling block transfers instructions from the Basic Module to the PLC-5 back plane.

• EIM … Controlinc 320A Quick Startup Guide, Rev. F or later

Publication No. ECL-4004-0102

This manual is used for specific information on the Controlinc 320A Controller card located in the valve actuator. This includes networking, setup and available options.

• EIM … Controlinc 320B Quick Startup Guide

Publication No. ECL-4005-0404

This manual is used for specific information on the Controlinc 320B Controller card located in the valve actuator. This includes networking, setup and available options.

• EIM … TEC2000 “Document … TBD”

Publication No. ?????????

At the time of this printing, this TEC2000 publication had not been made available.

• Other Allen-Bradley manuals specific to the PLC-5 being applied. These may be required to implement the necessary Relay Ladder Logic (RLL) for application of the driver. For instance, this may include:

o Allen Bradley PLC-5 Programmable Controllers Instruction Set Reference,

Publication 1785-6.1

This reference includes information in Chapter 15 on the AB Block Transfer Instructions, Block Transfer Write and Block Transfer Read.

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Controlinc 1771-C (Version 5.21) Network Master Users Guide (2004-11-18)

1.4. EIM Equipment Compatibility

The 1771-C is compatible with the following EIM equipment:

• 320A … version 1.17 and later.

• 320B … all

• TEC2000 … all

Other points:

• The 1771-C derives the system type of each actuator during the diagnostic scan and stores the results in table [18].

• The 1771-C derives the firmware Version ID for the 320A & 320B systems during the diagnostic scan and stores the results in table [19].

• Since the TEC2000 system has several micro-controllers with firmware, a special request must be made to them to derive the firmware version ID for each controller in the unit.

• The SSR bit is only checked and set on 320A actuators.

Note: For maximum compatibility with the TEC2000 systems, you should enable monitoring the

TEC2000 Status Inputs (tables [21-24]). This way, you can ensure you have all critical status information for any TEC2000 system on the network. For more information, refer to the section on Tables [21-24].

Note: This document references the addressable memory ranges (“Memory Maps”) of several EIM

actuators (ex: M2CP–320B, TEC2000). This is only for the reader’s convenience. The specific details in the memory maps are only correct as of the date this manual was published. Therefore, to ensure you have the most current memory information, please refer to the technical information for that particular actuator.

1.5. Firmware

The firmware is a “driver program” which is a compiled application program (not an interpreted one). It is loaded and stored in the module's 32K EEPROM (A-B P/N 1771-DBMEM2). The user is required to provide configuration information from the PLC Relay Ladder Logic (RLL) for each specific application (the RLL must load table [0] with appropriate configuration information).

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Controlinc 1771-C (Version 5.21) Network Master Users Guide (2004-11-18)

2. 1771-C Hardware

2.1. Hardware Setup

Refer to Chapter 1 of the 1771-DB manual. The following hardware jumper settings are required. If the 1771-DB module was supplied by EIM, jumpers are already set and no other settings are required.

For the 1771-C to run, the jumper settings on the DB module should be set as follows:

• JW1 - enable watchdog timer

• JW2 - 32K EEPROM

• JW3 - turbo

• JW4 - PRT1 = ASCII

- PRT2 = ASCII

- DH485 = PGM

• JW5 - 8-point mode

• JW6 - 9600 bit/s

• JW7 - enable battery

• JW8 - RS232

• JW9 - RS232

This jumper configuration is normally performed by EIM before shipping the 1771-C.

(Jumper settings are screened on the side of the 1771-DB module)

Figure 2-1 – Hardware jumpers of the 1771-DB

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Controlinc 1771-C (Version 5.21) Network Master Users Guide (2004-11-18)

2.2. LED Utilization

2.2.1. Green (PTX & PTR) and Yellow (LED1 & LED2) LED Usage

There are 2 “Yellow” LED lights on the front of the 1771-C module

• LED1.

• LED2.

There are currently 3 general functions operating these LEDs:

1. After CPU restart (power up or pressing the <RESET> button), both LED1 & LED2 are ON until the 1771-C finishes initialization and starts polling the network.

2. After initialization, LED1 is used as a “starting a new scan” indicator by toggling on/off at the start of each scan. Ex: Starting scan 1: LED1 is ON. Starting scan 2: LED1 toggles to the OFF state. Starting scan 3: LED1 toggles to the ON state.

3. After initialization, LED2 is used as an “entire network is down” indicator. If the 1771-C ever detects zero (0) actuators on the network, it will turn LED2 on and immediately enter a diagnostic scan and remain there until an actuator is found to be on-line and communicating.

There are 4 communication LED lights (green LED lights) on the 1771-C module:

• PT1X: Port 1 Transmit … lights up when transmissions are going out port 1.

• PT2X: Port 2 Transmit … lights up when transmissions are going out port 2.

• PT1R: Port 1 Receive … lights up when characters are being received on port 1.

• PT2R: Port 2 Receive … lights up when characters are being received on port 2.

If the network is in a valid ring configuration, then a transmission on either port will generate a receive indication on BOTH receive LEDs (PT1R & PT2R). Observing this is a sign that the ring topology is correct.

Manual

Reset

button/switch

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Green LED App Note:

After startup, if table [0] is not initialized shortly after the 1771-C finishes its initial diagnostic scan, the program starts running with factory default settings. This means that unless the network actually has 60 actuators on it, the 1771-C will believe the “other valves” are just off line. Plus, an operator can often determine when the PLC-RLL actually writes to table [0] (configures the system) by watching the green LED lights.

For instance …

• On a network that actually has 25 valves on it (addressed 1-25), until table [0] – word [4] gets initialized with 25, the program thinks that there are still supposed to be 60 actuators on the network … only the last 35 happen to be “off line”.

• Then (if viewing the green LED lights) when a scan starts (LED1 changes state), you will see the green LEDs “flash” while the 1771-C communicates with valves 1-25.

Then you will observe a “dead space” in time when the program is trying to determine if any of the final 35 valves “it believes to be connected” are available (and of course none are because the network only has 25 valves on it).

• As soon as a new scan starts (all “60” valves have been checked and ready to scan the network again … LED1 changes state) then the green LEDs will start flickering again while the 1771-C communicates with valves 1-25.

Then the “dead space” time will be observed again.

This sequence will repeat until the PLC program initializes the 1771-C by writing to table [0].

Controlinc 1771-C (Version 5.21) Network Master Users Guide (2004-11-18)

Green LED Lights & System Initialization with Table [0]

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Controlinc 1771-C (Version 5.21) Network Master Users Guide (2004-11-18)

2.2.2. Red “BTL” LED Usage

The red “BTL” LED indicates low battery status. The purpose of the battery in the DB module is to back up portions of RAM and other resources. For guaranteed long-term repeatability of operations, the EIM 1771-C program does not utilize any of these resources. Therefore, it doesn’t matter what state the battery is in (installed and fully charged, inline and dead or totally removed from the unit), the EIM network master program will always run the same.

This also means that a new 1771-C module might run with the BTL LED off for a while and then turn on when the battery dies. This is normal and has NO effect on the system. However, if for some reason you want to replace the battery, you can order it directly from Allen-Bradley.

“BTL”

LED

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Controlinc 1771-C (Version 5.21) Network Master Users Guide (2004-11-18)

3. Network Setup and Connecting to the NIU

In general, the EIM NIU (“Network Interface Unit”) is a “beefed up” and configurable RS232  RS485 converter.

The ports on the 1771-C, Port1 (PRT1) and Port 2 (PRT2), are configured for serial communication using RS-232.

The network communication parameters are pre-configured and fixed at 9600 baud – 8 bit – no parity – 1 stop bit.

The NIU isolates and protects the 1771-C and the PLC from the network and is powered by its own 120 AC circuit. Its primary function is to convert RS232 communications to RS485 communications. The RS485 connection then communicates to a ring or ring network.

Note: To help with isolation, there are two (2) entirely separate boards in the NIU. However, because of this, there are two (2) 120 VAC connections to the NIU. Ensure that both are connected (you can jumper the circuits together).

The Controlinc network is connected to the 1771-C module via the Network Interface Unit (NIU). It doesn’t matter if you connect:

• Port 2 (PRT2) (top DB25 connector): connects to the NIU at the port labeled “HOST A”.

• Port 1 (PRT1) (bottom DB25 connector): connects to the NIU at the port labeled “HOST B”.

• Port 1 (PRT1) (bottom DB25 connector): connects to the NIU at the port labeled “HOST A”.

• Port 2 (PRT2) (top DB25 connector): connects to the NIU at the port labeled “HOST B”.

However, it is recommended that you remain consistent.

NOTE: You can always connect a PC to the network at the NIU if you …

• Disconnect the cable connecting the 1771-C and NIU.

• Connect the PC using a (serial cable + NULL modem) to the DB9 connector on the NIU.

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Controlinc 1771-C (Version 5.21) Network Master Users Guide (2004-11-18)

A typical E>Net network connection format is in a ring …

• It starts from Port 1 (PRT1) (the top DB25 connector) on the 1771-C as RS232 and connects to the NIU at the port labeled “Host A”.

• It exits the NIU at the port labeled “Port A” as an RS485 circuit and proceeds to the first valve actuator, normally addressed as #1, in port A.

• It exits the actuator from Port B and proceeds to the port A next actuator (address #2) and on until the last actuator on the network is connected.

• The RS485 network then exits port B on the last actuator returns to the NIU at the port labeled “Port B”.

• The network connection is then transformed back to an RS232 format and exits the NIU via the port labeled “Host B”

• It connects to the 1771-C via port2 (PRT2) (the bottom DB25 connector).

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Controlinc 1771-C (Version 5.21) Network Master Users Guide (2004-11-18)

3.1. Field Connections at the Actuator

Communication connections and wiring are important for the network and the master.

(The following information was primarily derived from the Controlinc Quick Startup Guide)

3.1.1. Step 1. Plan the Network Topology

Before connecting actuators, the entire network layout should be planned. Topologies may be bus, redundant bus, E>Net, redundant E>Net, E>Net ring, and redundant E>Net rings. Planning should include node addressing, wire routing, terminations, and grounding.

3.1.2. Step 2. Select Network Cable

Ensure correct cable is being used.

• Networks require twisted pair and shielded cable with characteristic impedance between 50 and 120 Ohms.

• Capacitance between conductors must be less that 30 pF/Ft (98 pF/M); 10-15pF/Ft is ideal.

• Shielding maybe aluminum foil with drain wire.

• If cable has multiple pairs, then individual pair shielding is required.

• Only cables with stranded conductors are recommended.

• Insulating and outer jacket materials must be selected for the application environment.

The following are acceptable Belden or equivalent cables for most network applications.

AWG 20 18 16 14 Beldon # 8762 8760 8719 8720 Rating 12.8 Pf/fT 12.8 Pf/fT 12.8 Pf/fT 12.8 Pf/fT

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Controlinc 1771-C (Version 5.21) Network Master Users Guide (2004-11-18)

3.1.3. Step 3. Route Cable away from Electrical Interference

Network cables should enter the electrical enclosures and the bottom or lowest point (on 320A systems, this is near the transformer end and normally in a counter clockwise direction to the topside of the TBM). Never install network cable in the same conduit with power conductors. Never route the network cable through the high voltage contactor area. On 320A systems, the cable should never lie across the TBM or hinder the protective cover of the TBM. Always use the shortest distance and keep access cable to a minimum.

See Figure 3-1

3.1.4. Step 4. Observe Polarity and Network Grounding

Each network connection is polarized + and - on wiring diagrams. Always use consistency in wiring and the use of wire colors to track polarity. The cable shield (or “drain wire”) must be connected to the designated “shield” terminal at each port of each actuator. The shield must be connected to earth ground at only one point. Some networks require a jumper between the shield connections on ports A & B of the actuator to carry the shielding through the network. The shield connection of each actuator is isolated from earth ground. Do not allow the shield to touch other circuits or the metal enclosure.

Figure 3-1

Figure 4-1

Correct termination of the Network

to a Controlinc 320A Actuator

3.1.5. Step 5. Wire Preparation and Connections

Screw terminal connections on the TBM and in the TEC2000 terminal chamber have wire clamps, which will accept conductors with out terminals. Wire terminals may be applied if desired but are not required. Strip conductor insulation back 3/8” when connecting directly to the TBM screw terminals. Do not allow wire clippings to fall on the TBM or into the enclosure. Protect the conductors and shield to prevent them from contacting any other circuits or earth ground. Use plastic electrical tape or heat shrink tubing to prevent bare conductors from contacting other circuits or earth ground. See Figure 3-1

3.1.6. Step 6. Test Network

Use EIM’s Configuration and Control Utility (CCU) to test the network prior to connecting to the host or network master. The CCU is a Windows application, which will run on a laptop. Use a RS232 to RS485 adapter or EIM’s Network Interface Unit (NIU) to connect the laptop to the network. Test each actuator, one at a time, to determine that all network connections are good and each actuator is functional via the network in remote.

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Controlinc 1771-C (Version 5.21) Network Master Users Guide (2004-11-18)

3.2. Field Network Cable Connection to the NIU

Refer to Figure 3-2 for terminals on the EIM Network Interface Unit (NIU). The NIU is a dual port RS232 to RS485 converter specifically designed for ring networks.

Connect the twisted shielded pair cable of the field network to NIU Terminals 1 (-), 2 (Shield), 3 (+) of J1 of Port A.

The network shield must be connected to a good earth ground at only one shield terminal point on the NIU.

The network cabling should use recommended cabling for an RS-485 network able to handle the distance desired.

There should be little, if any, electrical noise on the network for the entire length of the network.

Ne twor k Por t

Shield

SW1

RXD

TXD

Ground

DB-25 Male

Connector

(1771-C Side)

R S - 2 3 2

P o r t

2 V A C / D C

RS232 Cable

J 2

P W R

N I U 8 4 3 2 0

(#37122)

Shield

Figure 3-2

DB-9 Male Connector (NIU Side)

Chassis

RXD

TXD

Ground

PWR

TxD

RxD

3.3. Cable Connection Between the NIU and the Network Master

Refer to the “Allen-Bradley 1771-DB, Series B Basic Module User's Manual” for additional information on the pin-out of the DB-25 female connections used for network ports one and two.

The module must be set up for RS-232 when connecting with EIM's Network Interface Unit (NIU) P/N 84320 or a user-supplied modem.

Refer to Figure 3-2 for the pin-out of the DB-9 female connector.

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Controlinc 1771-C (Version 5.21) Network Master Users Guide (2004-11-18)

4. 1771-C General Theory of Operation

4.1. Operational Overview

The interface for the PLC with the actuators (through the 1771-C module) is with an array of 25 tables … 64 words per table with the table number (command) in Word # [0] of each. This is based on the 64-word BTR/BTW interface protocol established by Allen-Bradley for the PLC-5 systems.

The 1771-C operates using a “Non-Interruptible Time-Slice Process Allocation methodology. This means that it must finish executing the process that is executing in its allocated time-slice before another process can operate. The two processes being scheduled are:

• Scanning the network for data.

• Interfacing with the PLC.

This means that the 1771-C will ignore any new commands from the PLC while scanning the network (during the network scan time-slice) and no network scanning will take place while processing a command from the PLC (during the PLC interface time-slice).

” communication

4.1.1. Diagram Describing Relationship Between Process Time Slices

Process time slicing is how the 1771-C divides its time when performing its 2 primary communication tasks … communicating with the PLC and communicating with the actuator network.

This diagram helps demonstrate the relationship between the two communication processes.

PLC

PLC  1771-C

Communications

(PLC Interface Time Slice)

1771-C

1771-C Actuators on

Network Communications

(Network Scan Time Slice)

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Controlinc 1771-C (Version 5.21) Network Master Users Guide (2004-11-18)

4.1.2. Diagram Describing Network Scanning & Actuator Writing Logic

This example demonstrates how a normal scan cycle gets elongated with data writes to the actuators. The more writes being performed the longer it will take to complete data scans. This is where the PLC/HMI must make a value decision for the best fit for their application:

• Fast enough repetitive writes to control the system

• Slow enough repetitive to ensure effective feedback to control the system.

Polling

for data

Time to poll 30

actuators for

data … without

any writing to

actuators

Polling

for data

actuators for data …

Performing 3 sets of

interspaced within

the single scan loop

Time to poll 25

data writes

Polling

for data

Polling

for data

Polling data …

“Network Scan

Time-Slice”

Writing

data

Writing data to the network … “PLC Interface

Time-Slice”

Writing

data

Writing

data

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Controlinc 1771-C (Version 5.21) Network Master Users Guide (2004-11-18)

4.1.3. Diagram Demonstrating Adding Additional Valves in Valve Scan Time-Slice

This example demonstrates how increasing the additional number of valves to be scanned before servicing the PLC communication task decreases the total network scan time.

This is where the PLC/HMI must make a value decision for the best fit for their application:

• Increasing the number: Speeds up data collection Lowers PLC control capabilities.

• Decreasing the number: Slows down data collection Increases PLC control capabilities.

Example of scale for time to scan network … different values for Additional valves in scan time slice:

Network size: 8 Network size: 8 Additional valves: 0 Additional valves: 3

(Note the relative time differences are for illustration purposes only … not to any exact scale.)

Poll 1 valve for data

Service PLC cmd

Poll 1 valve for data

Service PLC cmd

Poll 1 valve for data

Service PLC cmd

Poll 1 valve for data

Service PLC cmd

Poll 1 valve for data

Service PLC cmd

Poll 1 valve for data

Service PLC cmd

Poll 1 valve for data

Service PLC cmd

Poll 1 valve for data

Service PLC cmd

Poll 4 valves for data

Service PLC cmd

Poll 4 valves for data

Service PLC cmd

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Controlinc 1771-C (Version 5.21) Network Master Users Guide (2004-11-18)

4.1.4. Diagram Describing Relationship Between Scan Period & Diagnostic Scan

This example demonstrates the relationship between the diagnostic scans, scan periods, the current scan period, the previous scan period.

This example: a scan period value of 10 and 25 valves on the network. This means that all the valves on the network will be scanned 10 times before the scan period is over … and before the next diagnostic scan is performed.

(all 10 network scans of 25

Scan Period

valves completed)

Diagnostic

scan

Individual

network scans

Diagnostic

scan

Current

Scan Period

(so far, 5 network scans

completed)

Current time History

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Controlinc 1771-C (Version 5.21) Network Master Users Guide (2004-11-18)

4.1.5. 1771-C System Operations at Power Up

The 1771-C software boots up on a power up or a reset from depressing switch S1 on the 1771-C module. In general, on boot, the software will:

1. Illuminate LED1 & LED2 as an indication that the software is initializing itself and the network.

2. Perform basic internal initializations.

3. Perform the initial diagnostic scan of the network and identify all actuators on the network.

4. Finish internal initializations.

5. Turn off LED1 & LED2.

6. Start standard scanning of the network. Initialization is finished. Normal operations (scanning) have commenced and are allowing PLC communications. (LED1 toggles ON during the start of this first scan)

Note 1: Remember that the PLC cannot perform any block transfers until after the network master has

finished polling the network for status information and LED2 has been turned off and the 1771-C starts indicating that it is ready for data (after scanning starts).

Note 2: Even though LED1 turns off immediately after the initial scan after power up and then toggles

back on after normal operations start, the user will not normally see this … at the most it would be a small flicker. Therefore, to the user that is observing the LED behavior after restart on a system that has actuators communicating, it will appear that …

During the initial scan when the PLC cannot talk to the 1771-C … LED1 == ON LED2 == ON.

Immediately after the initial scan when normal operations start (start of 1 LED1 == ON LED2 == OFF.

normal scan):

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Controlinc 1771-C (Version 5.21) Network Master Users Guide (2004-11-18)

4.2. Network Interface (Scan) Time-Slice (1771-C ↔ Network Communication)

4.2.1. Operation: Network Scanning to Gather Valve Actuator Data

The Network Master polls and controls up to 60 valves on the network by sequentially polling (scanning) each device in sequence from slave actuator address #1 to the last slave address (#n) on its network. This polling gathers information from the actuators (including alarms, discrete information and actuator position) and places it in tables that can be transmitted to the PLC.

The scan operation cannot stop in the middle of a request for data from a particular actuator. Therefore, the 1771-C can only interface with the PLC once it has finished all required communications with the actuator it is currently getting data from. Network scanning resumes with the next actuator after interfacing with the PLC and processing any requests made by the PLC (writes to tables, writes to actuators, table reads, …).

For example, if the 1771-C is currently scanning actuator [5] and the PLC wants to write a new valve position setpoint to 22 actuators then the 1771-C will …

1. Finish getting data from actuator [5]

2. Get the new command table from the PLC.

3. Write the new valve position setpoint to all 22 actuators.

4. Restart network scanning where it left off … the next actuator [6] after the last one polled [5].

Standard data is gathered from the actuators by a single Modbus 03 command. However, a 2

• If requesting totalizer data

• If requesting a specific holding register

• If requesting a block of holding registers from this actuator

• If requesting to monitor the discrete outputs on this actuator

• If requesting TEC2000 input data.

This is one reason why additional data should only be requested when needed … it will slow the entire scan time of the system (by a minimum of 30-50 ms each time an actuator is polled for this data). For instance, if all 5 of the above are requested for each actuator, an extra 30-50 ms is required for EACH … meaning that the scan time could be increased by almost a factor of 5! … dramatically slowing down the system!

A typical scan time (time to scan all the actuators on the network) to gather “standard” information on 60 actuators is less than 10 seconds … depending upon the 1771-C configuration.

When gathering data, the data is stored in the appropriate tables in the 1771-C. Values in the table for a particular actuator will not be overwritten if there is an error communicating (on both ports) with the actuator.

Modbus 03 command is generated if any of the following are true …

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Controlinc 1771-C (Version 5.21) Network Master Users Guide (2004-11-18)

4.2.2. Operation: The Network Communication Diagnostic Scan

After a predetermined number of loops through the network scanning the actuators (the “scan period”), the 1771-C performs a communication diagnostic scan to determine if any “off-line” actuators can come back on line. If there are any that are ready, the 1771-C will bring them back on line without human intervention. This is the only time an off-line system can come back on-line.

The number of loops around the network is determined by the “scan period this value to accommodate site requirements and current operating environments.

Unlike the other operations that access the actuators on the network, the diagnostic scan checks both ports when communicating with the actuators. Because of this, it also always takes longer to execute than standard data gathering scans. However, normal data is still gathered during a diagnostic scan.

The only major difference in data gathering between a standard scan and a diagnostic scan is

• In the diagnostic scan, the 1771-C determines actuator system type and actuator firmware version ID (tables [18 & 19]).

• Both ports are explicitly tested when getting the system type information.

• The diagnostic scan ensures that the hardware ports are set correctly … 9600 - 8N1.

Otherwise, all other data gathering activities are the same as in a normal network scan.

Communication error indications may only be cleared during this scan.

The “scan loop counter

” is always zero (0) during a diagnostic scan … the diagnostic scan does not count as part of the scans in the scan period. This is the only time the loop counter is zero … during the diagnostic scan.

The diagnostic scan time increases as you increase the discrepancy between the

(number of valves actually on line and talking

) VS (the number of valves configured to be on line)

Below shows a sample of diagnostic scan times empirically taken on a network when there was no network “writes to the actuators” (Table [0] was configured for 60 valves). As you can see, as you increase the number of “off line” units, you increase the diagnostic scan time.

# Nodes “Talking” … On-Line

60 of 60 (#1 – 60) 10 54 of 60 (#7 – 60) 11 48 of 60 (#13 – 60) 12 42 of 60 (#19 – 60) 13 36 of 60 (#25 – 60) 15 30 of 60 (#31 – 60) 16 24 of 60 (#37 – 60) 17 12 of 60 (#49 – 60) 19 6 of 60 (#55 – 60) 20 3 of 60 (#58 – 60) 21 2 of 60 (#59 – 60) 22 1 of 60 (#60) 22

Diagnostic Scan Times (secs)

Version 5.21

” value. The PLC adjusts

The values in this table

“rounded values” and

have a precision of (+/-) 1

second.

Because of this, these

numbers are only

appropriate for estimates

and trend analysis.

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Controlinc 1771-C (Version 5.21) Network Master Users Guide (2004-11-18)

Notes:

• Though not much, the diagnostic scan time can also vary with the number of valves in the valve scan time slice.

• The greater the number of valves configured to be on line, the longer the diagnostic scan time … more valves to check.

• During normal operations, an operator can use the HMI to force the system into a diagnostic scan by temporarily changing the “scan period” value in table [0] to a value lower than the current scan loop counter. This will cause the program to enter a diagnostic scan as soon as this scan loop has finished.

• Because the diagnostic scan detects faulty communication ports and flags them, there can be a perceived increased performance in the normal network scans because “off-line” actuators have already been flagged and will be skipped.

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Controlinc 1771-C (Version 5.21) Network Master Users Guide (2004-11-18)

4.3. PLC Interface Time-Slice (1771-C ↔ PLC Communication)

The primary interface for the PLC with the 1771-C module is with an array of 25 tables (labeled 0  24) stored in the 1771-C RAM. Each table is 64-words long and each word is 16-bits. From the perspective of the PLC interfacing with the network, some of the tables are “read only” and some are “read/write” (depending upon a command word).

The Relay Ladder Logic (RLL) in the PLC CPU interfaces with the 1771-C module by using BTR/BTW block transfers to transfer fixed blocks of 64 words with the table number (command) in Word # [0] of each transfer.

Relative to BTW/BTR commands, from the 1771-C perspective, there is no difference in handling “table reads” or “table writes”. They both require a BTW/BTR set of block transfer commands.

During the PLC interface time-slice, the 1771-C uses 2 functions to request BTW/BTR operations. These function calls are “time locked” in that the 1771-C must remain in the function waiting for a response from the PLC before it can resume network monitoring activities.

If the timer expires before the PLC sends the BTW/BTR command:

• The function terminates.

• If a request for a BTW, the PLC interface time-slice terminates.

• If a request for a BTR, the 1771-C

o The 1771-C sends the table anyhow. o The 1771-C performs any other required actions like writing values to the actuators. o The PLC time-slice terminates.

Once the PLC interface time-slice terminates, the PLC must wait until the next PLC interface time-slice starts before there is another chance at a BTW/BTR command.

A side effect of this is that it is possible for the entire network scan time to slow down if the 1771-C has to wait to get data from the PLC before it can continue with collecting data from the valves.

Control is based on bits 13 (DN) & 15 (EN) in control word [0] in the BT data structure. These are the standard block transfer control bits and the PLC and back plane is normally control setting and clearing these bits.

Note

: If a BTW command is never issued by the PLC (or received by the 1771-C), the PLC interface

time-slice terminates and the 1771-C will never request a BTR to send a table back to the PLC.

Note

: Refer to the following Allen Bradley Documents:

• Allen Bradley PLC-5 Programmable Controllers Instruction Set Reference, Publication 1785-6.1

• Allen-Bradley 1771-DB, Series B Basic Module User's Manual Catalog No. 1771-DB, Series B, Publication No. 1771-6.5.113

Page 25

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